Change KubeResourceManager API

[kornys]

Description

Change API of KubeResoruceManager

1. deprecated getInstance() method and use instead of get() method for getting instance
2. Context set/get methods moved from static to non-static
3. YAML path configuration method moved from static to non static

Type of Change

Please delete options that are not relevant.

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit/integration tests pass locally with my changes